A sputtering method is commonly known as a method of forming a thin film on a substrate surface. The sputtering method is widely known as a dry process technique that is essential for a film deposition technique. The sputtering method is a method of depositing a film by introducing a rare gas such as Ar gas into a vacuum container and supplying direct current (DC) power or high frequency (RF) power to a cathode including a target to cause a glow discharge.
The sputtering method includes a magnetron sputtering method capable of depositing a film at a high speed by increasing plasma density near the surface of a target by placing a magnet on the back side of the target in an electrically grounded chamber. Such a sputtering method is used by a process of forming a predetermined thin film on, e.g., a processing substrate having a large area such as a glass substrate forming a liquid crystal display panel etc.
For example, Patent Document 1 discloses that in a magnetron sputtering apparatus having a plurality of targets arranged at predetermined intervals and parallel to a substrate to be processed, an alternating current (AC) voltage that alternates in polarity at a predetermined frequency is applied to each target to cause a glow discharge with anode and cathode electrodes being alternately switched between each pair of adjoining targets, whereby a plasma atmosphere is produced.
On the other hand, Patent Document 2 discloses that in a magnetron sputtering apparatus having a plurality of targets to which a voltage of the same polarity is applied, the substrate is moved parallel to the targets.